This invention relates to an industrial endoscope system for inspecting the interior of an automobile engine or the like.
Recently, there are extensively used medical endoscopes which can be inserted in an elongate insertable part into a body cavity to observe organs within the body cavity or, as required, through a catheter channel to collect tissues within the living body by using a catheter and diagnose the affected part in detail. In the industrial field, there are also extensively used industrial endoscopes by which the interior of a boiler, turbine, engine or chemical plant can be observed or inspected.
A sheath for internally inserting a light guide bundle of an illuminating means, removably fitted on the outer periphery of the insertable part of the above mentioned endoscope, is disclosed in the publication of Japanese Utility Model Application Publication No. 31672/1973.
An industrial endoscope in which the insertable part is coated with a metal blade to improve the durability is disclosed in the publication of Japanese Patent Application Laid Open No. 37322/1982.
Further, a rigid sheath fitted with a reflecting mirror for converting the visual field is disclosed in the publication of Japanese Patent Application Laid Open No. 149118/1986.
As mentioned above, various sheaths removably fitted on the outer periphery of the endoscope insertable part are known.
However, the removably fitting structure to the endoscope is different in the respective sheaths. Various sheaths different in the removably fitting function can not be used as combined for one endoscope. That is to say, one endoscope can be combined with only one sheath. Therefore, there have been problems that the endoscope is limited in use and, as many endoscopes as there are uses must be prepared, and an economic burden is placed on the user.